Ground Launched Small Diameter Bomb (GLSDB)

timmymagic said:
TomS said:
And South Korea, I believe.
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I know that the 227mm rockets from M270/HIMARS are compatible with the K239 Chunmoo, but not sure if it works the other way TBH. Interesting if it is the case, particularly for Poland as they've got a split buy of Chunmoo and HIMARS on the way.
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Fair point. I suppose it's possible that there is one-way compatibility but it seems unlikely.
 
TomS said:
timmymagic said:
TomS said:
And South Korea, I believe.
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I know that the 227mm rockets from M270/HIMARS are compatible with the K239 Chunmoo, but not sure if it works the other way TBH. Interesting if it is the case, particularly for Poland as they've got a split buy of Chunmoo and HIMARS on the way.
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Fair point. I suppose it's possible that there is one-way compatibility but it seems unlikely.
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It will depend upon which version of rocket. From what I understand the K239 Chunmoo fires 3 main types of rocket:
  • K33 131 mm unguided rockets
  • KM26A2 230 mm rockets which are based on the M26 227 mm unguided DPICM rocket
  • 239 mm guided rockets
Presumably it would only be the KM26A2s which have any sort of dual commonality.
 
GTX said:
It will depend upon which version of rocket. From what I understand the K239 Chunmoo fires 3 main types of rocket:
  • K33 131 mm unguided rockets
  • KM26A2 230 mm rockets which are based on the M26 227 mm unguided DPICM rocket
  • 239 mm guided rockets
Presumably it would only be the KM26A2s which have any sort of dual commonality.
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The 239mm guided rocket is the same size as GMLRS-ER, which is why I suspect it might also have some commonality, given that Chunmoo launchers can also handle GMLRS-ER.
 
From Defence Updates concerning the GLSDB package that will arrive soon in Ukraine:


The United States has answered President Volodymyr Zelenskiy's plea for weapons that can strike deep behind the front lines of the nearly year-long conflict with Russia.
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The Pentagon has stated that the latest $2.17 billion in aid to Ukraine will include an unspecified number of Ground Launched Small Diameter Bombs (GLSDB).
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The weapon officially referred to as "precision-guided rockets" on the aid package, will significantly aid Ukraine's attempts to retake territory from Russia by giving its troops the capacity to hit targets at distances much greater than the longest-range munitions delivered to Kyiv till now.
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This development was first reported by Reuters. In this video Defense Updates analyzes how GLSDB could be a game-changer for Ukraine?
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Some remarks were deleted from the description concerning political statements.

When I think about it I still find myself scratching my head that once the Boeing/SAAB team successfully demonstrated the concept it wasn't put into production, it uses off-the-shelf components (Except for the adapter that mates the SDB-I to the M26 rocket-motor) so it is very cheap.

I'd be interested to the Boeing/SAAB team extend this concept to include the SDB-II and the SPEAR 3.
 
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Triton said:
Artist's impression of Boeing GL-SDB (Ground Launched Small Diameter Bomb).

Boeing is modifying the Small Diameter Bomb with a rocket motor to be launched from ground-based missile systems such as the M270 MLRS. After the motor launches it to a high enough altitude and speed, the wings will deploy and glide the bomb to its target. The company believes it can fill a gap for long-range precision fires. While typical MLRS systems follow a ballistic trajectory, the rocket-launched SDB can be launched to an altitude and glide on a selected trajectory. Boeing is planning on a demonstration in 2014.
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Source:
defense-update.com

Future Fires to Focus on Precision, Clean Weapons - Defense Update:

In recent years the role of armaments and weapons in military exhibitions is diminishing, reflecting the diminishing role of kinetic effects and the complex public perception as to their role in modern asymmetric warfare. Hence, the armaments and munitions presented at AUSA and the Modern Day...
defense-update.com defense-update.com
en.wikipedia.org

GBU-39 Small Diameter Bomb - Wikipedia

en.wikipedia.org en.wikipedia.org
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AN/AWW-14(V) said:
DO6dya4UMAAdHBd.jpg:large


Saab will test its Ground-Launched Small Diameter Bomb (GLSDB) later this month, with officials hoping the flight will push the 140km mark for the first time.
The last time the system was fired, a 2017 test in the US, the distance reached was short of 100km. Reaching 140km in the latest test would represent close to maximum range for the system.

MSPO 2019: Saab aiming for 40% range bump in next GLSDB test fire | Shephard

Saab will test its Ground-Launched Small Diameter Bomb (GLSDB) later this month, with officials hoping the flight will push the 140km mark for the fir
www.shephardmedia.com
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Ground Launched SDB t be provided to Ukraine.
 
From some reports on Ukraine it appears that the Ukrainian army may've received the GLSDB as they conducted several missile strikes against Russian army targets in Mariupol which was something like 50 miles behind the frontlines.
 
NMaude said:
From some reports on Ukraine it appears that the Ukrainian army may've received the GLSDB as they conducted several missile strikes against Russian army targets in Mariupol which was something like 50 miles behind the frontlines.
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Most news reports suggested spring 2023 at the earliest and quite a few said nine months from contract award, which would be September/October timeframe.

www.reuters.com

Factbox: U.S. rocket-powered bomb would double Ukraine's strike range

The United States is expected to send a new weapon to Ukraine, the Ground Launched Small Diameter Bomb (GLSDB), doubling Kyiv's current strike range.
www.reuters.com www.reuters.com


It seems likely that this is something else. Why not renewed drone attacks or special operations forces? Heck, for max secret squirrel factor, the Black Hawk that they just showed off may have been used to test armament kits, so we might be seeing something like a budget DAP at work.

www.thedrive.com

UH-60 Black Hawk Unexpectedly Appears In Ukrainian Military Service

An apparent former U.S. Army UH-60A has appeared in Ukrainian military service, with the shadowy Defense Intelligence directorate.
www.thedrive.com www.thedrive.com
 
TomS said:
Most news reports suggested spring 2023 at the earliest
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Northern spring starts next month so that's not far off.

TomS said:
quite a few said nine months from contract award, which would be September/October timeframe.
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I find that surprising since the US has some 400,000 surplus M26 rocket-motors in storage and the SDB I is already in full-scale production so the only thing new that needs to be manufactured is adapter unit to mate the SDB to the M26.
 
NMaude said:
I find that surprising since the US has some 400,000 surplus M26 rocket-motors in storage and the SDB I is already in full-scale production so the only thing new that needs to be manufactured is adapter unit to mate the SDB to the M26.
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It needs to be productionized -- thus far, all they've done is a few test rounds. It's possible there are a few prototype rounds around, but it's been literally several years years since the last test flight, so I am skeptical. Also, I'd want to put in place some sort of inspection process on the M26s, x-raying them for cracks, etc. They're pretty old, and mostly sitting around waiting for disposal, so not necessarily in great condition. Setting up a reliable procedure for that will take time, especially to do it at scale.

Also, let's consider the source for the claim that GLSDB is in use. It's entirely from Russian sources. Which have also claimed that Russians forces have already destroyed Ukrainian M1 tanks (there aren't any) and started claiming to have destroyed Bradleys long before any reached Ukraine. There were even claims that they must have used ATACMS to hit the Kerch Bridge. Etc.

Why take their statements at face value when there are alternative explanations? We've seen explosions like this happening behind Russian lines for weeks, before anyone started talking about GLSDB. Could just as easily be loitering munitions, saboteurs, etc.
 
Question1
M26 rocket engine has 4 wrap fins to stable by spinning.But SDB can not fly while rotating. So how to?
Question 2
The dimensign of M26 is D227mm, but the cross area of SDB is more than D227mm。That means the launch tube of HIMAS can not contain SDB.So，how to launch the GLSDB?
 
Blueking said:
M26 rocket engine has 4 wrap fins to stable by spinning.But SDB can not fly while rotating. So how to?
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After the M26 rocket-motor has burned out the SDB separates and deploys its' tail-fins then deploys its' wings (Which will dramatically reduce its roll-rate) before using said tail-fins to eliminate any remaining spin.
 
Blueking said:
Question 2
The dimensign of M26 is D227mm, but the cross area of SDB is more than D227mm。That means the launch tube of HIMAS can not contain SDB.So，how to launch the GLSDB?
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The launch tube for MLRS is substantially wider than 9 inches, with interior rails for rifling. The SDB is not much (if any) bigger than the M26 judging from the models I've seen, but there is room on the tube if they need it. Just need to remove some rifling.
 
TomS said:
Blueking said:
Question 2
The dimensign of M26 is D227mm, but the cross area of SDB is more than D227mm。That means the launch tube of HIMAS can not contain SDB.So，how to launch the GLSDB?
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The launch tube for MLRS is substantially wider than 9 inches, with interior rails for rifling. The SDB is not much (if any) bigger than the M26 judging from the models I've seen, but there is room on the tube if they need it. Just need to remove some rifling.
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And the Bomb part of the SDB1 is bout 6 inchs or 155mm in diameter. Seen specs saying 160mms.

Assuming that not including the wings assembly the entire bomb is in all likelyhood LESS them 200mm or roughly 8 inchs. And I have Seen specs saying its 7.5 inch/190mm at the widest point.

Which is roughly an inch in a half two inchs, either way more then 30mms of spare space with the Rifling.

So there is more then enough room for it.
 
Saab and Boeing are not saying exactly how this works (and I can't find a patent) but I suspect the interstage between the M26 rocket and the SDB payload has a despin function, either during launch or after booster separation.
 
TomS said:
It needs to be productionized -- thus far, all they've done is a few test rounds.
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True however I wouldn't surprised if the Boeing/SAAB team drew up such plans after the successful conclusion of the tests.

TomS said:
Also, I'd want to put in place some sort of inspection process on the M26s, x-raying them for cracks, etc. They're pretty old, and mostly sitting around waiting for disposal, so not necessarily in great condition. Setting up a reliable procedure for that will take time, especially to do it at scale.
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That's a good idea but I'm sure that no doubt Boeing already has plans in place to set up the x-raying of the available M26 rocket-motors. Now as to the condition of the rocket-motors that really depends on how well they were stored. In addition to x-raying M26s for crack I imagine that once Boeing has obtained the number of motors they want I could see them randomly selecting a few and test-firing them to see how they perform.

TomS said:
Saab and Boeing are not saying exactly how this works (and I can't find a patent) but I suspect the interstage between the M26 rocket and the SDB payload has a despin function, either during launch or after booster separation.
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While that's possible IMO I think that's more likely that the rate of rotation will be slowed by the deployment of the tail-fins and the wings due to conservation of angular-momentum with any residual rolling being dampened out by the control-fins.
 
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One wonders how much cheaper, allowing for size of production run, a guided, gun-launched projectile is than a pocket-propelled one with the same level of performance.
 
Kat Tsun said:
1635yankee said:
One wonders how much cheaper, allowing for size of production run, a guided, gun-launched projectile is than a pocket-propelled one with the same level of performance.
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Similar to or more expensive per kill.
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Depending on brains in the shell, the quick references I found for M982 Excalibur and Ground Launched GBU39 put the advantage well in favor of the cannon projectile, even with recycling existing and paid for rocket motors for the GLSDB.
 
Scott Kenny said:
Kat Tsun said:
1635yankee said:
One wonders how much cheaper, allowing for size of production run, a guided, gun-launched projectile is than a pocket-propelled one with the same level of performance.
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Similar to or more expensive per kill.
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Depending on brains in the shell, the quick references I found for M982 Excalibur and Ground Launched GBU39 put the advantage well in favor of the cannon projectile, even with recycling existing and paid for rocket motors for the GLSDB.
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GLSDB doesn't exist outside of marketing brochures. Not sure where you got the idea it's more expensive than a Excalibur though. It has like three times the range so it's probably worth it anyway. You also found some weird references, because GBU-39 is cheaper than M982, as of FY2023. $48,000 USD versus $100,000 USD on average.


A Stormbreaker costs twice as much as M982 but can hit moving targets without external guidance. It's still cheaper than a Javelin, because it's a glide bomb deployed by aircraft. Excalibur is a single 155mm shell with an INS kit. It's $70,000. Copperhead was similarly expensive, but can hit moving targets, but also requires a ground designator team which needs to be emplaced and in the proper position...

A self-guiding Copperhead would probably cost similar to Stormbreaker or Javelin, so six digits (maybe twice as much as Excalibur), because it requires shock hardened electronics.

Once you factor in the ancillary equipment like laser designators, or amount of munitions needed to be expended to hit mobile targets, the advantage of the single unit cheaper shell tends to evaporate. Per pound of explosive, a missile or rocket will always deliver more killing power for less cost, at least when it comes to delivering ordnance against wide area targets, than shells.

Excalibur persists mainly due to minimum range issues with GMLRS and relative paucity of M270 rocket launchers in inventory, not due to its own merits. If CLGPs were good, you wouldn't have dumb artillery in the Navy, and every tank would fire laser guided long-rods. Unfortunately, they aren't, which is why engagement costs between a single anti-ship missile like Griffin ($140,000) and a dozen laser-guided 57mm shells ($160,000) are more similar than they are alike.

Often this is to the detriment of the CLGP, because you need a dozen ALaMOs to deliver the same explosive mass as a Griffin (more, actually, but we're being generous and assuming ALaMO performs decently okay with the rough equivalent of a 40mm grenade inside it).

CLGPs trade cost per pound of explosive delivered (a rough approximation of killing power) for the ability to be fired from more platforms. That is rarely an optimal trade and they are often used to expand the capability of existing systems instead. Compared to the cost of a rocket alone, CLGPs are bad, but compared to the cost of a brand new artillery system and crew training schedules and whatnot, CLGPs are great.

If the choice is between stapling Starstreaks to the side of a vehicle, or giving it laser guided shells, the choice is obvious: Starstreak.
 
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Kat Tsun said:
Scott Kenny said:
Kat Tsun said:
1635yankee said:
One wonders how much cheaper, allowing for size of production run, a guided, gun-launched projectile is than a pocket-propelled one with the same level of performance.
Click to expand...

Similar to or more expensive per kill.
Click to expand...
Depending on brains in the shell, the quick references I found for M982 Excalibur and Ground Launched GBU39 put the advantage well in favor of the cannon projectile, even with recycling existing and paid for rocket motors for the GLSDB.
Click to expand...

You found some weird references, because GBU-39 is cheaper than M982, as of FY2019. $40,000 USD versus $85,000 USD.

A Stormbreaker costs twice as much as M982 but can hit moving targets without external guidance. It's still cheaper than a Javelin, because it's a glide bomb deployed by aircraft. Excalibur is a single 155mm shell with an INS kit. It's $70,000. Copperhead was similarly expensive, but can hit moving targets, but also requires a ground designator team which needs to be emplaced and in the proper position...

A self-guiding Copperhead would probably cost similar to Stormbreaker or Javelin, so six digits (maybe twice as much as Excalibur), because it requires shock hardened electronics.

Once you factor in the ancillary equipment like laser designators, or amount of munitions needed to be expended to hit mobile targets, the advantage of the single unit cheaper shell tends to evaporate. Per pound of explosive, a missile or rocket will always deliver more killing power for less cost, at least when it comes to delivering ordnance against wide area targets, than shells.

This is one of those immutable things and is the main reason why multiple rocket launchers have survived for 75+ years in military use.

Rockets are better for delivering large blast-type warheads to kill particularly annoying things, like warships or reinforced structures, while cannons and aviation bombs are better at delivering penetrating warheads due to the high speeds they impact. It would be hard to fit a reinforced bunker buster into a GMLRS but trivial to fit a blast-frag warhead or DPICM, which can annihilate soft targets like C3I and SAM sites.
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GROUND LAUNCHED SDB, not a basic GBU-39.
 
Scott Kenny said:
Kat Tsun said:
Scott Kenny said:
Kat Tsun said:
1635yankee said:
One wonders how much cheaper, allowing for size of production run, a guided, gun-launched projectile is than a pocket-propelled one with the same level of performance.
Click to expand...

Similar to or more expensive per kill.
Click to expand...
Depending on brains in the shell, the quick references I found for M982 Excalibur and Ground Launched GBU39 put the advantage well in favor of the cannon projectile, even with recycling existing and paid for rocket motors for the GLSDB.
Click to expand...

You found some weird references, because GBU-39 is cheaper than M982, as of FY2019. $40,000 USD versus $85,000 USD.

A Stormbreaker costs twice as much as M982 but can hit moving targets without external guidance. It's still cheaper than a Javelin, because it's a glide bomb deployed by aircraft. Excalibur is a single 155mm shell with an INS kit. It's $70,000. Copperhead was similarly expensive, but can hit moving targets, but also requires a ground designator team which needs to be emplaced and in the proper position...

A self-guiding Copperhead would probably cost similar to Stormbreaker or Javelin, so six digits (maybe twice as much as Excalibur), because it requires shock hardened electronics.

Once you factor in the ancillary equipment like laser designators, or amount of munitions needed to be expended to hit mobile targets, the advantage of the single unit cheaper shell tends to evaporate. Per pound of explosive, a missile or rocket will always deliver more killing power for less cost, at least when it comes to delivering ordnance against wide area targets, than shells.

This is one of those immutable things and is the main reason why multiple rocket launchers have survived for 75+ years in military use.

Rockets are better for delivering large blast-type warheads to kill particularly annoying things, like warships or reinforced structures, while cannons and aviation bombs are better at delivering penetrating warheads due to the high speeds they impact. It would be hard to fit a reinforced bunker buster into a GMLRS but trivial to fit a blast-frag warhead or DPICM, which can annihilate soft targets like C3I and SAM sites.
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GROUND LAUNCHED SDB, not a basic GBU-39.
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How do you have figures about something that doesn't exist? No one has purchased GLSDB, therefore it has no recorded cost...

Comparing the non-existent GLSDB and the M982 is disingenuous. One doesn't exist and the other has a third the range (150 vs 50 km), so it's apples to oranges in two ways. GLSDB would have a range comparable to the Navy's aborted LRLAP, which costs around $1 million FY2016 which are the latest figures, but I think GLSDB would have cost less than the near "Tomahawk missile" costs of the 100 nmi ranged CLGP.

Anyway, this thread is about Starstreak. If you have to pick between making laser guided 25mm shells or slapping Starstreaks on the side of a vehicle, you'll choose the Starstreak if you're sensible and of sound mind that is motivated by combat performance. People have different motivations, and different competencies, so they choose different things. For the most part, CLGPs are compromised in unit cost and engagement cost compared to maneuvering missiles.

Starstreak's darts are around 20-25mm diameter and the missile is from the 1980's. However, there's a reason no one was rushing to get 35mm, subcaliber, laser guided HTK shells into a Gepard when they could just put Stingers on the sides at the time. It isn't because Germany couldn't do this. It's because CLGPs are typically the worse option.

The U.S. military vacillates between generally cogent decisions (Excalibur, Copperhead, PGK) that fit the peculiarities of the CLGP to decisions that make people question the motivations of the acquisitions officers (ALaMO, LRLAP, SLRC).

There seems to be the idea that CLGPs are cheaper than rockets, which sort of meanders through the E-Ring every few years, and this might be because people are comparing things like TOW and Copperhead or Excalibur with Javelin, or someone is suggesting a 50 gram explosive warhead is comparable to a 5,000 gram warhead against small craft, or whatever. This filters through to the press and makes ordinary laymen think the same. It's a bit bizarre. CLGPs typically require multiple engagements per attack, not because they don't hit, but because their explosive masses are so much smaller than a rocket.

Rockets carry bigger warheads which means more killing. Shells carry smaller warheads which means less killing.

Thinking this way tends to result in the belief of the superiority of the MRL to the cannon writ large, which is probably true, but there aren't enough MRLs in anyone's inventory to fully displace the cannon and the minimum range issues remain. In a world with infinite resources and instant timescales, I guess large caliber MRLs (220-300mm) and 120mm mortars would be the only pieces of the artillery park since they maximize the ability to kill the enemy.

Obviously you work with what you have, though. CLGPs are a good way to give precision guidance to a howitzer, one that would otherwise require two or three minutes to fire a dozen shells when it can fire two shells at the same target in 30 seconds for the same price and similar effectiveness instead.

They aren't good for engaging small targets in general though. They tend to cost as much per engagement as dumb rounds, you're just taking less time, expressed by fewer shells, to kill the target. You're still paying the same amount of money.

Nuclear weapons are the only time this shifts in favor of the attacker, I think. Even a small thermonuclear weapon can destroy much more value for money than the $2-4 million it nominally costs.
 
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NMaude said:
About bloody time! With the GLSDB will Ukraine be able to reach targets in Crimea?
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Some of it, yes. Dzhankoy will be in range for instance. Lugansk city also, Mariupol, Berdyansk etc. And Taganroy airbase in Russia's Rostov region.
 
timmymagic said:
Pretty certain that the US will have received assurances that actual Russian territory will be off limits unfortunately..
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Generally yes, but there was that exemption for returning fire. So hypothetically if Russian aircraft took off from there to launch an attack against Ukraine, they could return fire when they land.
 
Interesting to note it was pretty much a direct hit, indicating that enemy EW did not have much effect. Also interesting is that it was 60km behind enemy lines, so the Grads were not in a position where they could even hit their own front line troops, let alone the enemy.

View: https://www.youtube.com/watch?v=BgkcXf30j88
 
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Once the GLSDB is deployed in large numbers the Ukrainians can start attacking and destroying Russian ammunition dumps, command HQs, armoured vehicle and truck parks, supply warehouses, barracks radar sites, SAM sites and various electronic warfare sites that were out of range of the GMLRS missiles.
 

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